No one can touch Amazon when it comes to the breadth and size of its content library and today’s announcement just reinforces the notion. The online retail giant has cut a landmark and unheard-of deal with Home Box Office Inc. (HBO), an American premium cable and satellite television network that in my opinion has the best original TV shows anywhere.

Under the terms of the exclusive multi-year agreement, both Amazon Prime members and owners of the recently introduced $99 Fire TV set-top box will soon be able to stream HBO’s old shows three years after they’ve aired and at no additional charge. Catch 22: HBO is reserving new shows for existing subscribers and you’ll need to subscribe to Amazon’s $99 per year Prime Instant Video service.

Still, this is huge. Firstly, you won’t need an HBO cable TV subscription at all to stream the shows. And secondly, online-only subscriptions to HBO were previously non-existent. Now, Apple TV owners are able to access HBO content via the HBO GO app on their Home screen, but this requires a subscription with a cable or satellite provider and therefore doesn’t appeal to cable-cutters…

Amazon notes that the deal makes its Prime Instant Video service the exclusive online-only subscription home for select HBO programming, such as its famous series like The Sopranos, Six Feet Under, The Wire, Big Love, Eastbound & Down, Oz, Band of Brothers and Deadwood, early seasons of Boardwalk Empire and True Blood and more.

Mini series likeBand of Brothers, John Adamsand more are also part of the content deal.

Previous seasons of other HBO shows, such asGirls, The Newsroom and Veep, will become available over the course of the multi-year agreement, approximately three years after airing on HBO, said the company.

Prime subscribers can expect the first wave of content to arrive on May 21:

All seasons of revered classics such as The Sopranos, The Wire, Deadwood, Rome and Six Feet Under, and of recent favorites such as Eastbound & Down, Enlightened and Flight of the Conchords

Epic miniseries, including Angels in America, Band of Brothers, John Adams, The Pacific andParade’s End

Select seasons of current series such as Boardwalk Empire, Treme and True Blood

Hit original movies like Game Change, Too Big To Fail and You Don’t Know Jack

Pedigreed documentaries including the Autopsy and Iceman series, Ghosts of Abu Ghraib andWhen the Levees Broke

Notably absent: HBO’s popular Game of Thrones fantasy series, adapted from George R. R. Martin’s series of fantasy novels titled A Song of Ice and Fire, because the show is “too valuable” for the network, according to Peter Kafka of Re/Code.

New shows like Game of Thrones are not part of the deal.

“This is the first time that HBO programming has been licensed to an online-only subscription streaming service,” notes Amazon. “This programming will remain on all HBO platforms.”

HBO GO provides access to more than 1,700 titles, including every episode of new and classic HBO series, as well as HBO original films, miniseries, sports, documentaries, specials and a wide selection of blockbuster movies.

Fire TV customers will be able to stream the shows via the upcoming HBO GO app for their box that should arrive by year end.

Analysts were quick to warn that the Amazon-HBO deal poses a grave threat to Netflix as the agreement makes Amazon the “king of original content.”

Until now, if you wanted to watch old episodes of, say, Big Love online, the only place you could stream it legally (without paying to buy or rent it from Amazon or iTunes outright) was HBO Go, which requires a cable subscription (1).

By separating HBO’s programming from the cable bundle and licensing it to Amazon, HBO is giving the people what they want: quality television, whenever they want it, without spending a fortune.

Again, despite HBO shows being available for rent or purchase through iTunes, it’s the first time HBO has been available for unlimited consumption online through a service other than HBO Go.

With this deal, Amazon has just raised the water level on its platform’s functionality. In my personal opinion, the kind of premium HBO content included in the agreement totally justifies spending a hundred bucks on that Prime membership.

Amazon recently raised prices of Prime membership from $79 to $99 per year and now we see that the price hike was totally justified. Prime membership includes both the Prime Instant Video service and two-day shipping on Amazon.com.

If you’re a Prime subscriber, you’ll be able to access the aforementioned HBO shows, as well as all current Prime programming, through Amazon’s free Instant Video app for the iPhone and iPad, now with iOS 7 styling and other bells and whistles.

Amazon is not currently offering subscription video within Prime in Canada, France, Italy, Spain or Japan, though they may choose to expand the service to these markets as well. For the time being, Prime Instant Video is available only in the United States, United Kingdom and Germany.